Charge forming device



Oct. 24, 1933; F. E. ASELTINE CHARGE FORMING DEVICE Filed May 23, 1930 3Sheets-Sheet l Oct. 24, 1933. F. E. ASELTINE 1,931,599

CHARGE FORMING DEVICE Filed May 25', 1950 3 Sheets-Sheet 2 Oct. 24,1933.

F. E. ASELTINE CHARGE FORMING DEVIC E Filed May 23, 1930 3 Sheets-Sheet5 p. Mn W WE 2/2 /76 x72 /90 2/! J INVENTOR BY 5 M WM) ATTORNEYSPatented Oct. 24, 1933 UNITED STATES 1 1,931,599 cannon roams nnvrcnFred E. Aseltine, Dayton, Ohio, assignor to Delco 7 ProductsCorporation, Dayton, 0hio,'a corporation of Delaware Application May 23,1930. Serial No. 454,914 12 Claims. (01. 261-47) This invention relatesto charge forming devices for internal combustion engines and moreparticularly to devices of this character which comprise a plurality ofprimary carburetors, each of which delivers a. primary mixture of fueland air to one of a plurality'of secondary mixing chambers locatedadjacent to the engine intake ports and in which the primary mixture ismixed with additional air under certain operating conditions. Devices ofthis character are shown in the copending application of Fred E.Aseltine et a1, Serial Nos. 360,404 and 370,179, filed May 4, 1929 andJune 12, 1929 respectively. This invention is shown herein as embodiedin both of these devices, since its action-is somewhat different in thedifferent constructions.

It is the general object of the present invention to provide means forcontrolling thev admission of secondary air so as to restrict the amountof air supplied through the secondary air passage under all operatingconditions inaccordance with the engine suction.

More specifically it is an object of the invention to provide devicesfor controlling the movement of the secondary air valve which areeffective to permit the movement of the valve toward open position bysuction of the engine, are effective under certain operating conditionsto move the valve toward closed position to a degree determined by thesuction of the engine and under other operating conditions are effectiveto close the valve as the throt-le is closed.

These objects are accomplished accordingto the present invention by theprovision of means operated by the throttle for closing the valvemechanically as the throttle is closed, the provision of a valve whichisoperable entirely by engine suction on its openingmovements and theprovision of a weight for moving the valve toward closedposition onreduction of enginesuction, while the throttle remains inflxed position,to a position where the .engine suction balances the effect of theweight.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being hadto the accompanyingdrawings wherein a preferred embodiment of oneform of the presentinvention is clearly shown.

In the drawings:

Fig. 1 is a vertical section through the carburetor unit and one outletbranch of the manifold.

Fig. 2 is a left side elevation of the carburetor as shown in Fig. 1.

of the housing by any suitable means'and my unit partly broken away toshow certain parts in section.

Fig. 3 is a fragmentary elevation of the carburetor unit viewedfromtheleft in Fig. 2.

Figs. 4, 5 and 6 are views similar to Figs. 1, 2 and 3 respectivelyshowing the invention embodied in a modified form of carburetor.

Fig. 7 is a detail view of a valve operating connection embodied in theform of device shown in Fi s. 1 to 3.

Fig. 8 is a detail view of partof the device shown in Figs. 4 to 6.

Fig. ,9 is a diagrammatic view of the device shown in Figs. 4 to 8inclusive. v

The device disclosed in Figs. 1 to 3 and 7 comprises a main air manifold10,'havin'g threeoutlet branches, the middle branch 12, being shownherein, each of these branches communicates .with one of the intakeports of a multi-cylinder engine and-each is provided with an attachingl6 flange 16 for securing the manifold to the engine block in the usualway,- while adjacent its inlet v the manifold is provided with a flange.18 to which the main carburetor unit is' adapted tube secured Thecarburetor unit comprises a main housing 20, having a flange '22,adapted to be' 'secured to the flange 18 by screws 24. An air inletcoupling 28 is securedin an openin in the top be connected to an aircleaner if desired.- A casting 28, in which the passages supplying fuelto the nozzles are formed, issecured inany dcsirable manner to thebottomof the main housing and a fuel bowl 30 is'held tight against the bottomof'said housing by any suitable means. Fuel is supplied to the bowl bymeans not shown, and a float '32 maintains a substantially constantlevel of fuel therein in the usual way,

Twofuel nozzles 34 and 36 are provided in each primary mixing chamber38, the structure of which is more fully described later. The nozzle 34supplies all of the fuel at idling andrelatively lowspeed operation, anda part of the fuel at all other times while the'nozzle 36 is ineffectiveuntil the throttle has been opened a-considerable-distance and theengine is running at relatively high speed;- The nozzles are. suppliedwith fuel through separate fuel passages; that supplying the nozzles 36being closed at relative 106 low speed operation. The fuel nozzles, thepassages supplying fuel thereto'and means for controlling'the flowtherefrom are fully shown and described in the earlier of the aboveapplications, such structure forming no part of this invention. no

Both nozzles 34 and 36 are provided with restrictions 40 to regulate theflow therethrough.

Each low speed fuel nozzle isprovided with a main fuel outlet 42 in thetop 01. the nozzle and a secondary fuel outlet comprising two orifices I44 and 46 in the wall of the nozzle near the bottom of the mixingchamber, said nozzles functioning in the manner set forth in application360,404.

The primary mixing chambers form the enlarged inlet ends of primarymixture passages 48 which are parallel and close together. When thecarburetor is secured to the manifold these passages register withprimary mixture conduits which convey the primary mixture to thesecond-,- ary mixing chambers. Restrictions 50 separate the mixingchambers from the remainder of the primary mixture passages, andpassages 52 admit air immediately posterior to the .restrictions toreduce the velocity of flow past the nozzles, all of this structurebeing fully described in application 360,404.

A single primary throttle valve 54 operated in a manner briefiydescribedhereinaiter extends top of the air valve.

across all of the primary mixture passages to control the flowtherethrough, and is provided with grooves 56 which register with suchpassages.

Air entering the carburetor is supplied through the coupling 26 and iscontrolled by a main air valve 58 normally held against a seat 60, by aspring 62 received between the valve and a flange 64 projecting from asleeve 66, slidably mounted on a stationary sleeve 68, fixed in the mainhousing and guiding the air valve stem 70. In order to choke thecarburetor to facilitate starting, the valve may be lifted by means,(not shown) until the sleeve 66 engages the air valve to hold it closed.Air to carry the starting fuel to the intake ports is admitted throughslots 72 in the The valve 58 admits air to an air chamber 74 from whichit flows to the primary mixing chambers through an opening '76 in thebottom of the inlet, and controlled by manually operated valves and 82,secured to shafts 84 and 86 respectively mounted in the main housing,the valve 80 being hereinafter termed a. secondary throttle", forconvenience.

'[ The operating means for the primary and secondary throttles forms nopart of this invention and is not illustrated herein, but the mode ofoperation of the throttles will now be briefly set forth in order toenable a better understanding of the operation of the whole device. Thesecondary throttle is operated by the primary throttle through themedium of operating mechanism which permits certain independent movementof the'primary throttle and is generally designed to permit the primarythrottle to move independently of the secondary until it reaches aposition corresponding to a vehicular speed of approximately 15-20 milesper hour on a level.

cylinder. The cylinder is filled with fuel by leakage around the pistonand the resistance of the dash pot is controlled by an auxiliary piston92 in the manner fully described in application 360,404. However, thestructural details of the dash pot are not material to the presentinvention and any conventional dash pot may be employed.

As previously stated the primary mixture passages communicate, when thedevice is assembled, with conduits fcrmed in the manifold. The middleone of these conduits is shown herein and comprises a straight passage94 in the manifold casting in which is received a tube 96 which extendsthrough the branch 12 of the manifold. The conduits supplying primarymixture to the two end branches of the manifold are of the form shown inthe earlier application.

The valve 82 is opened, on opening of the valve 80, as in the earlierapplication, entirely by engine suction and the opening movement of thevalve is temporarily retarded for the same purpose, this being to retardthe flow of pure air through the secondary air passage while increasingthe velocity of flow through the primary mixture passages in order tofacilitate enrichment of the mixture during the-acceleration.

erally from a bell crank lever' 102, rotatably' mounted on a boss 104projecting from the main housing and in which'the shaft 86 isjournalled. The bell crank lever has an arm 106 which is pivotallyconnected to a short link 108 pivotally connected to a lever 110 pivotedon a pin 112 screwed intothe main housing and connected at-its opposite"end to a rod 114. This rod extends to a piston (not shown) which isslidable in a dash pot cylinder'116, the top of which is shown in Fig.2. The dash pot is of exactly the same construction as that of theapplication 360,404, and in order to simplify this disclosure as much aspossible has not' been shown herein.

Normally, when the valve 80 is closed the valve 82 is held closed by aspring 117, connected" at one end to an arm 119, secured to the oppositeend of shaft 84 and at its other end to a link 121 having slots 123 and125 therein through which project pins'127 and 129, extending from'thearm 119 and an arm 131 secured to the end of shaft 86, respectively.This construction is shown in Fig. 7 and the parts are held in theposition shown therein, when the throttle is closed. In this positionthe spring 117 is tensioned and through the medium of the link 121,pulls the arm 131 to the left to move the valve 82 in a clockwisedirection to closed position. On opening movement of the throttle thearm 119 is moved counter-clockwise relieving the tension of spring 117and permitting the valve 82to open under influence of engine-suction,while on closing movement of the throttle, the clockwise movement of arm119 again tensions the spring to efiect closing of the'valve 82, all

nections extending to the dash pot piston, the latter is lifted untilthevalve assumes the position determined by the' suction. If thethrottle be opened wide; and theengine be operating at high speed, thevalve 82 will occupy a sub-- stantially horizontal position. If,however. the

load is increased, as'when'the vehicle on which the device is employedascends a hill,'the engine speed is decreased with a correspondingdecrease in suction. Under such conditions the auxiliary air valve 82willtend to move toward closed position. In the device disclosed in ap--plication 360,404, when the valve 82 is positively connected to the dashpot piston-there is nothing position.

According tothis invention the valve is not directly connected to thedash pot piston so its closing movement on decrease ofsuction, is notaffected by the piston, and means are provided to move the valverelatively rapidly to the position determined by the engine suction.*This means comprises a weight 120 which. is secured "to the shaft 86and extends substantially horizontally therefrom, when the valve is inclosed position, as in Fig. 2, so that the greatest effect of the weightis had when the valve nears its closed position and the suctioneifective on the valve is relatively low. This weight causes the valveto float in the air stream and when the throttle is in fixed position,causes the valve totake different positions in accordance withthesuction effective on the valve, and to move to suchpositionsrelatively rapidly as the suction changes. On suchmovements ofthe valve 82, the dash pot piston and connected parts move slowly untilthe arm 98 engages this arm 100. On closing movements of the throttle80, the valve is closed by the closing spring as in the earlier device,while the dash pot piston and associated parts are moved to normalposition as previously described.

It was found that in the device shown inapplication 360,404,insufficient restriction to the admission of secondary air might occurtemporarily. on operation at heavy load with widev I the medium of thearm 1 54 and pin 156. If, how- 125 ever, the throttle and the valve,arewide open and an increase of load occurs, a decrease in sucopenthrottle, resulting at times in too low suction at the fuel jets in theprimary'mixture passages. and a. temporarily insuiiicient supply offuel. This invention is effective to produce at all times the properdegree of restriction on the flow of secondary air, to form a mixture ofcorrect proportions under all operating conditions.

The construction of the secondary mixing chambers and other elements'ofthis device, which have not been shown and described herein aresubstantially the-same as in the earlier'application and no furtherillustration is thought necessary.

In the deviceshown in the later application 370,179, the piston of thedash pot which controls motion of the auxiliary air valve is'moveddownwardly when the valve is opened. Consequently, on decrease ofsuction in the secondary air passage under such operating conditions aspreviously referred to, the auxiliary air valve will not close at allbeing held open by the weight of the dash pot piston and connectedparts. The above described weight for closing the auxiliary valve istherefore even more useful in the later form of charge forming devicethan the earlier: and its application thereto is shown in Figs. 4, 5, 6and 8.

'present invention."

and138 respectively jou'rnalled in the main hous- The openingmovement-df -the-valve 134 is retarded by a dash pot comprising a'cylinder 140 and a piston 142 slidable therein, a check :valve '--144operating to prev'ente'scape of fuel from the cylinder on opening of thevalve but permitting a For the purpose of simplifying the disclosure asmuch as possible} the specific construction'of this later device willnot be incorporated herein except those parts immediately'associatedwith the In the device shown in Figsg' 4, 5, 6 and 8 the secondary airpassage isindicated at 130 and is controlled by a secondary-throttle1-32and "a suction operated valve 134 secured to shafts 136 free returnmovement ofthe dashpot piston. The piston 142 is pivotally connected toa'link 146 which at its upper end is pivotally connected to an arm148,-which, in the device shown in application 370,179 was secured tothe shaft 138 on which the auxiliary valve is mounted. Ac-" cording tothis invention the arm 148 is pivotally mounted on the shaft 138 andisadapted to be engaged by a toe 150 projecting laterally from an arm152 secured to the shaft 138 adjacentthe arm 148. On opening movementsof the auxiliary valve the toe 150 'engages the arm 148 to move the dashpot piston downwardly, the opening of the valve thus being retarded bythe 'dash shown in FigI-S, when'thethrottle'is closed. In

this position a pivoted arm-154 is' 'hel'd in en: gagement vn'th' a pin156 projecting-fromthe link 146 by'a spring '158, -'one end of which isconnected to-anear 160- projecting from the arm 154 andthe other't'o a'pin 162 projecting from the main housing. On opening of the throttle apin 164 is moved into engagement withthe arm 154' and then moves saidarm out of en-. gagement with the pin 156 to permit the valve 134 to beopened by engine suction inthemanner fully described in application370,179. On-clos- 1 ing movement of the throttle thepin 1641s restoredto normal'position' and'the spring1-58 operates to close the auxiliaryair valve through tion is produced and the auxiliary air valve shouldclose'to an extent-determined by the reduction in suction. -With thestructure disclosed inap- 13 plication 370,179 this was impossiblebecause nothing was'provided to close the'valve and the weight of thedash pot piston and connected. parts would operate to hold the valvewide open, resulting in unsatisfactoryengine operation under suchcircumstances. According to this invention a weight 166 is provided-toclose the valve 134 to a position where the weight is balmoved. Theauxiliary'air valve is thus moved to a position under all operatingconditions which is dependentupon the engine and at all times terminedby that suction.

Fig.9 is a diagrammatic viewof the device shown in Figs. 4to Sinclusive,and is provided primarily to show the arrangement of the fuel passageswhich supply fuel to the mixing chambers, for normal operation andduring acceleration, the throttle, air valves and the operating 7connections therefor andthe dash pots which J control such air valves.The structure disclosed is verybriefly described hereinafter, merely tofacilitate an understandingof the general construction and operation of:the device.

A plurality of fuel inlets 160 and 162 are provided and supplyfuel toeach one of three air is formed, the emulsion passing through orifices166 into angular primary mixture passages 168, there being three ofthese passages as shown in Fig. 6 and all of such passages arecontrolled by a primary throttle 170. A fuel passage 172 having aconstantly open low speed fuel inlet 174 and two-high speed fuel inlets1'16 and 1'78,

the effectiveness of which is controlled by valves 180 and 182respectively, the valve 180 being manually operated and the valve 182being operated by an arm 184 projecting from a rod 186 connected to theprimary throttle for operation therewith and adapted to operate a pumppiston 188 for supplying fuel during the acceleration period and morefully, described hereinafter.

- The pump piston 188 as it moves downwardly expels fuel from a cylinder190 in which the piston slides through a passage 192 connecting with avertical passage 194 controlled by a check valve 196 and delivering fuelto an auxiliary fuel reservoir 198, open to the air in the space abovethe fuel in the float chamber 201. Fuel is supplied from'this auxiliaryreservoir to the primary mixture passages through orifices 200 in thevfloor of such passages, one of such outlets being shown in Fig. 9. Fuelis supplied-to the float chamber byya conduit 202 and its flow iscontrolled by a float 204 in the usual way.

An air valve 206 corresponding to the valve 58 of Fig. 1' has a dash,pot piston 207 secured to the lower end of the stem on which the valveis mounted, such piston sliding in a cylinder 208 to which fuel isadmitted through orifice 210. Opening of the secondary or auxiliary airvalve 134 causes downward movement of the piston 142, as previouslydescribed. Movement of this piston is resisted by the piston 212slidable in the cylinder 214 and normally retained in the bottom of suchcylinder by the spring 216, an orifice 218 permitting a fiow of fuelfrom the cylinder 140 into the cylinder 214. After movement of thepiston 142 ceases, the piston 212' is moved by thespring 216 to theposition shown in the drawings so that any subsequent opening of thevalve 134 is resisted-inthe same mannerand to the same degree.

While the form of embodiment of the present invention as hereindisclosed, constitutes a preengines, comprising a mixture passage, meansfor supplying fuel and air thereto, a throttle, an auxiliary air valvefor controlling admission of air to said mixture passage, said valvebeing operated by engine suction on opening move- ;.ments of saidthrottle, means controlled by restricts the admission of air; to adegree cle-,

the throttle for closing the valve as the throttle is closed and othermeans for moving the valve toward closed position while the throttle.remains stationary, said additional closing means being so constructedthat the closing force exerted thereby on the valve is entirelyindependent of the position of the throttle.

2. A charge forming device for multicylinder engines,,comprising amixture passage, means for supplying fuel and air thereto, a throttle,an

auxiliaryair valve for controlling admission of air to said mixturepassage, said valve being operated by engine suction on openingmovements of said throttle, means controlled by the throttle for closingthe valve and other means operated automatically to move said valvetoward closed position-undercertain operating conditions, saidautomatically operated means being constructed to exert a closing forceon the valve which is independent of the position of the throttlecontrolled means whereby the closing effect of said automaticallyoperated means may be constant while the position of the throttlecontrolled means varies or may be variable while the throttle controlledmeans remains in fixed position.

3. A charge forming device for multicylinder engines, comprising amixture passage, means for supplying fuel and air thereto, a throttle,an

auxiliary air valve for controlling admission of air to said mixturepassage, said valve being operated by engine. suction on openingmovements of said throttle, manually operable means for closing thevalve, and gravity actuated means operable under certain operatingconditions for -moving the valve'toward closed position, said through, aspring for normally closing said valve,

manually operable means for preventing the closing of said valve bythespring, and other means independent of the spring and said manuallyoperable means for closing said valve under certain operatingconditions.

5. A charge forming device for internal combustion engines comprising asecondary mixing chamber, a primary carbureting. means adapted todeliver a primary mixture of fuel and air to said secondary mixingchamber, a secondary air passage supplying air to said secondary mixingchamber, a main air valve controlling the admission of air to both saidprimary carbureting means and secondary mixing chamber, a suctionoperated valve in said secondary air passage for controlling the fiowtherethrough, and gravity operated means operable to move said lastmentioned valve toward closed position to a degree determined by theengine-suction. 6. A charge forming device for intemal' combustionengines comprising a mixture passage,

means for supplying fuel and air thereto, a throttle, an auxiliary airvalve controlling admission opened on opening movements of the throttle,a dash pot for retarding opening movements of said auxiliary air valvebut constructed to exert no closing efl'ect on said valve and a weightoperable to move said air valve toward closed position independently ofthe dash pot.

7. A charge forming device for internal combustion engines comprising amixture passage,

' means for supplying fuel and air thereto, a throttle, an auxiliary airvalve controlling admission of air to said mixture passage and adaptedto be opened on opening movements of the throttle, a dash pot forretarding opening movements of said auxiliary air valve but constructedto exert no closing effect on said valve, an arm secured to the shaft ofsaid valve and having a one way connection with the dash pot pistonwhereby the valve is permitted to move toward closed positionindependently of the dash pot, and a weight secured to the valve shaftand adapted to move the valve toward closed position.

8. A charge forming device for internal combustion engines comprising asecondary mixing chamber, a primary carbureting means adapted to delivera primary mixture of fuel and air to said secondary mixing chamber, asecondary air passage supplying air to said secondary mixing chamber, amain air valve controlling the admission of air to both said primarycarbureting means and secondary mixing chamber, manually and suctionoperated valves in said secondary air passage for controlling theflow-of air therethrough and gravity operated means for moving the,suction operated valve toward closed position under certain operatingconditions inde pendently of the positionof the manually operable valve.

9.,A charge forming device for multicylinder engines, comprising amixture passage, means for supplying fuel and air thereto, a throttle,an aux=- iliary air valve for controlling admission of air to saidmixture passage, said valve being operated by engine suction on openingmovements of said throttle, means controlled by the throttle for closingthe valve as the throttle is closed, means operable on reduction ofengine suction to move the valve toward closed position while thethrottle remains stationary and constructed so as to exert the sameclosing force in any one position of the valve, irrespective of theposition of the throttle.

10. A charge forming device for multicylinder engines, comprising amixture passage, means for supplying fuel and air thereto, a throttle,an auxiliary air valve for controlling admission of air to said mixturepassage, said valve being operated by engine suction on openingmovements of 'said throttle, means controlled by the throttle forclosing the valve as the throttle is closed, means operable on reductionof engine suction to move the valve toward closed position while thethrottle-remains stationary and constructed to exert a progressivelyincreasing closing force as the valve moves toward closed position.

11. A charge forming dezice for multicylinder engines, comprising amixture passage, means for supplying fuel and air thereto, a throttle,an auxiliary air valve for controlling admission of air to said mixturepassage, said valve being operated by engine suction on openingmovements of said throttle, means controlled by the throttle for closingthe valve as the throttle is closed, means operable on reduction ofengine suction to move the valve toward closed position while thethrottle remains stationary, said means comprising a weighted armmovable with the valve and adapted to be moved from a position in whichit extends in a substantially horizontal plane when the valve is closedtoward a position in a vertical plane as the valve opens, whereby theclosing force exerted by the weight decreases as the valve moves towardopen position.

12. A charge forming device for internal combustion engines comprising amixture passage, means for supplying fuel and air thereto, a suctionoperated auxiliary air valve for admitting air to the mixture passage, aspring for normally holding said valve closed, a throttle forcontrolling the flow through the mixture passage, means operable by thethrottle as it is opened to prevent the spring from holding the valveclosed when the throttle is not in closed position, and other meansoperable independently of the spring and the throttle for moving thevalve toward closed position under certain operating conditions.

FRED E. ASELTINE.

Ill

